Basis for the exercise-induced hyperphagia in adult hamsters

Abstract

In adult female golden hamsters (Mesocricetus auratus, Waterhouse) voluntary exercise is associated with increased food intake and accelerated somatic growth. We examined the possible interdependence between increased food intake and accelerated somatic growth by measuring food intake in hamsters whose growth was blocked by hypophysectomy. In a 2 x 2 design, hypophysectomized hamsters (HYPOX, n = 20) and animals with intact pituitaries (INT, n = 24) were either allowed to exercise for 35 days (n = 22) or were maintained in sedentary condition (n = 22). Exercise induced increased food intake in both HYPOX and INT hamsters and somatic growth in INT hamsters only. Hypophysectomy was also associated with a 43% reduction in the activity level and a significant increase in the percentage of body fat estimated indirectly. We conclude that adult hamsters increase their food intake in response to some stimulus related to exercise and not to exercise-induced growth.